The longitudinal distribution of macroinvertebrates and fish in a lower niger delta river river sombreiro in nigeria

Nwadiaro C.S.

1984

Hydrobiological Bulletin 18(2): 133-140

The longitudinal distribution of macroinvertebrates and fish in a lower niger delta river river sombreiro in nigeria

The longitudinal distribution of macroinvertebrates and fish in a lower Niger delta river (river Sombreiro) was studied from Nov. 1979 to June 1982. When combined with an earlier study on the physico-chemical features of the river (Nwadiaro, 1984), 2 zones could be discerned. These are an upstream, soft, acid freshwater reach, approximately 86 km long, inhabited mainly by insects, with the dwarf cichlid fish Pelvicachromis Chromidotilapia complex as the distinctive fish type and a downstream, hard, neutral to slightly alkaline brackish water zone, about 30 km long, populated mainly by Crustacea (shrimps and crabs) and mollusks, with Monodactylus sebae as the characteristic fish. The diversity of macroinvertebrates and fish in the upstream zone was higher than in the downstream zone.